The characterization and quantification of individual chemical and complex biological molecules is extremely important in fields such as medicine, environmental protection, security, military, and other areas. The determination of individual chemical and complex biological molecules is currently complex and generally requires sophisticated and bulky equipment.
Even though many commercial products along with hundreds of patents have been filed in chemical and biological sensor field, sensor technologies to date are generally used to detect a single type or very few different types of molecules. None of them are particularly adapted to allow a very large number of different types of chemical or biological molecules to be detected.
In order to develop a highly selective, highly sensitive, and universal sensor system, a micro- or nano-sensor array with multiple different sensing elements, each connected to its own specific transducer, has been regarded as one of the possible ultimate solutions. Sensor arrays offer several advantages over single sensors. For example, sensor arrays have better sensitivity to a wider range of analytes. Such arrays offer better selectivity, multi-component analysis, and analyte recognition, rather than mere detection. Sensor arrays are more analogous to olfaction systems containing multiple receptors, whose responses are interpreted by neuron odor recognition processes.
Many existing technologies can be used to build a normal or mini scale of sensor arrays with multiple different sensing elements; examples of such technologies include e-beam lithography, selective thermo deposition, etc. However, none of the above-mentioned technologies work well in the micro- or nano-region. Selectively introducing different types of sensing elements onto different transducers in the micro- or nano-region and providing the micro- or nano-sensor array with multiple different sensing elements have been under active investigation. However, actually achieving these goals has been a challenge, due to the difficulties associated with how to selectively introduce different types of sensing elements onto different transducers in the micro- or nano-region.
Thus, there is a need for different types of sensing elements on different transducers, as well as sensor arrays with multiple different sensing elements, both in the micro- and nano-regimes.